On 11 January 2022, Nikopolidis was drafted by the New York Red Bulls II with the 71st pick in the 2022 MLS SuperDraft.
[2] Nikopolidis made his professional debut on 2 April 2022, during a 3–2 loss to FC Tulsa.
[3] Nikopolidis earned his first professional shutout on 15 July 2022, during a 1–0 win over Indy Eleven.
[4] Nikopolidis signed with Greek Super League side Lamia in January 2023.
[5][6] He was named to the bench for Lamia's 2–1 Greek Football Cup quarterfinal win vs. Apollon Paralimnio.